Adapting selective terrain warnings as a function of the instantaneous maneuverability of a rotorcraft

1. A method of generating a terrain avoidance warning for a rotary wing aircraft comprising: generating an avoidance trajectory including a proximal segment representative of a transfer time and an avoidance curve including at least one distal segment of a conic section curve following on from the proximal segment, wherein the proximal segment extends in continuation from a predicted trajectory over a distance representing an applicable reaction time, the applicable reaction time being minimized as a function of a route sheet for the aircraft; and wherein the generating includes calculating the at least one distal segment as a function of an instantaneous maneuverability of the aircraft.

2. The method as recited in claim 1 , wherein the proximal segment is rectilinear.

3. The method as recited in claim 1 , wherein the applicable reaction time is minimized as a function of the route sheet and of a parameter representative of a model of the aircraft.

4. The method as recited in claim 1 , wherein an applicable reaction time is minimized as a function of the route sheet and divided by at least one limiting ratio representing a flight parameter of the aircraft.

5. The method as recited in claim 1 , wherein the conic section curve includes a section of one of a parabola, an ellipse and a hyperbola.

6. The method as recited in claim 1 , wherein the conic section curve is calculated in real time as a function of up-to-date data produced by at least one of an avionics unit, a maneuverability indicator system and a flight computer.

7. The method as recited in claim 6 , wherein up-to-date data include at least one of a possible vertical acceleration value and an instantaneous mass value for the rotary wing aircraft.

8. A terrain warning device disposed at least in part on board an aircraft comprising: an avionics unit having a flight computer configured to execute a code, wherein the code is configured to generate an avoidance trajectory including a proximal segment representative of a transfer time and an avoidance curve including at least one distal segment of a conic section curve following on from the proximal segment, the proximal segment extending in continuation from a predicted trajectory over a distance representing an applicable reaction time, the applicable reaction time being minimized as a function of a route sheet for the aircraft; and wherein the at least one distal segment is calculated as a function of an instantaneous maneuverability of the aircraft.

9. The terrain warning device as recited in claim 8 , wherein the terrain warning device is logically coupled to a maneuverability indicator system.

10. A rotary wing aircraft comprising: a terrain warning device disposed at least in part on board the aircraft including an avionics unit having a flight computer configured to execute a code, wherein the code is configured to generate an avoidance trajectory including a proximal segment representative of a transfer time and an avoidance curve including at least one distal segment of a conic section curve following on from the proximal segment, the proximal segment extending in continuation from a predicted trajectory over a distance representing an applicable reaction time, the applicable reaction time being minimized as a function of a route sheet for the aircraft; and wherein the at least one distal segment is calculated as a function of an instantaneous maneuverability of the aircraft; and a sound alarm logically coupled to the terrain warning device and configured to be triggered selectively by the terrain warning device.

11. The rotary wing aircraft as recited in claim 10 , wherein the rotary wing aircraft is at least one of a helicopter, a convertible rotary wing aircraft, and a drone.